A fixed protocol stack structure is adopted by a relevant wireless transmission technique, and data needs to be added with a corresponding data head for each protocol layer, so as to be identified by different protocol layers. Taking a Long Term Evolution (LTE) system as an example, an air interface user plane 2 includes a Packet Data Convergence Protocol (PDCP) layer, a Radio Link Control (RLC) layer and a Medium Access Control (MAC) layer. A data packet processed by the user plane 2 is transmitted to a physical layer 1, and then processed such as being encoded and modulated at the physical layer 1 into a bit stream to be transmitted through the air interface. The PDCP layer has a header compression function and an encryption function, and after the header compression and encryption, an Internet Protocol (IP) data packet is taken as a PDCP Service Data unit (SDU), which is added with a PDCP header so as to form a PDCP Protocol Data Unit (PDU) transmitted to the RLC layer. The RLC layer has a segmentation function and a concatenating function. At the RLC layer, the PDCP PDU becomes an RLC SDU. The RLC layer may group a plurality of RLC SDUs into one RLC PDU, or segment one RLC SDU into a plurality of RLC PDUs. The MAC layer has a multiplexing function, and it may concatenate the RLC PDUs (also called as MAC SDUs for the MAC layer) from a plurality of bearers into one MAC PDU. The MAC PDU is then transmitted to the physical layer where a Cyclic Redundancy Check (CRC) addition and any other physical layer modulation and encoding treatment are performed, so as to generate a transmission block to be transmitted through the air interface. Upon the receipt of the bit stream from the physical layer, a receiver may parse the IP data packet in a process reverse to that mentioned above.
Due to a hierarchical modular design, architecture of an LTE protocol stack is generic to various service data, but it is not sufficiently advantageous to specific data transmission, e.g., signaling transmission and small-volume data transmission. Taking an Internet of Vehicles as an example, small data packets are mainly transmitted, and each vehicle may transmit a large number of small data packets each in 1 to 100 bytes. In the case that the LTE protocol stack is adopted, as compared with valid information, excessive overhead may occur for the header submitted by each protocol layer.
All in all, it is impossible for a specific terminal with the fixed, modular protocol stack to achieve an optimal effect at a specific application scenario, in terms of transmission efficiency, time delay, processing complexity, cost overhead, power consumption, and etc. In addition, in the case that special requirements need to be met, e.g., at a scenario where the time delay is highly restricted, it is impossible for a commonly-designed fixed modular multi-layer protocol stack to meet the time delay requirement.